Rollins Nieves (cottonshock20)

The benthic hypoxic environment in late-summer was more favorable for upward migration and diffusion of As. This process was considered as an important contribution to the elevated aquatic As in the Changjiang Estuary.Globally, the demand for sustainable energy production and high-value biological compounds have become intertwined in an attempt to improve the feasibility of sustainable algal cultivation. Marine microalgae, especially diatoms and coccolithophores, represent viable cultures that can produce biofuels and high-value compounds. Growing them in co-culture offers the potential to produce lipids and pigments, while also generating CaCO3 for C sequestration. The main objective of this work was to investigate competition or co-existence of the diatom Chaetoceros gracilis and the coccolithophore Pleurochrysis Carterae. The focus was on the effects of silicate and co-culturing on the growth rate, productivity, pigment production, and ash production for C. gracilis and P. carterae in laboratory conditions. The results showed that, in monoculture, 2-mM Si enhanced the specific growth rate of C. gracilis, but did not affect P. carterae. Regardless of silicate concentration, C. gracilis was more productive than P. carterae. In co-culture, P. carterae had a slower growth rate, indicating an inhibitory effect of C. gracilis on P. carterae. Neither silicate concentration nor co-culturing had an impact on the contents of pigments fucoxanthin, chlorophyll-a, and chlorophyll-c, which means that pigment productivity was proportional to biomass productivity. Finally, the ash content increased in all cultures with the lower silicate concentration (0.2 mM) in the medium. With one exception, the ash content was dominated by SiO2 regardless of silicate amount, and CaCO3 was a major part of the ash only when P. carterae was grown separately with the higher silicate level. These results highlight that co-culturing did not provide an advantage for improving biomass, pigments, or CaCO3 productivity.The occurrence of green-tides, whose bloom potential may be increased by various human activities and biogeochemical process, results in enormous economic losses and ecosystem collapse. In this study, we investigated the ecophysiology of the subtropical green-tide forming alga, Ulva ohnoi complex (hereafter U. ohnoi), under simulated future ocean conditions in order to predict its bloom potential using photosynthesis and growth measurements, and stable isotope analyses. Our mesocosm system included four experimental conditions that simulated the individual and combined effects of elevated CO2 and temperature, namely control (450 μatm CO2 & 20 °C), acidification (900 μatm CO2 & 20 °C), warming (450 μatm CO2 & 25 °C), and greenhouse (900 μatm CO2 & 25 °C). selleck chemical Photosynthetic electron transport rates (rETR) increased significantly under acidification conditions, but net photosynthesis and growth were not affected. In contrast, rETR, net photosynthesis, and growth all decreased significantly under elevated temperature conditions (i.e. both warming and greenhouse). These results represent the imbalance of energy metabolism between electron transport and O2 production that may be expected under ocean acidification conditions. This imbalance appears to be related to carbon and nitrogen assimilation by U. ohnoi. In particular, 13C and 15N discrimination data suggest U. ohnoi prefers CO2 and NH4+ over HCO3- and NO3- as sources of carbon and nitrogen, respectively, and this results in increased N content in the thallus under ocean acidification conditions. Together, our results suggest a trade-off in which the bloom potential of U. ohnoi could increase under ocean acidification due to greater N accumulation and through the saving of energy during carbon and nitrogen metabolism, but that elevated temperatures could decrease U. ohnoi's bloom potential through a decrease in photosynthesis and growth. Exposure to phthalate